Date-to-epoch input must include Z or a numeric timezone offset. Browser dates have millisecond precision.
How to use this unix timestamp converter
- Choose Unix timestamp or ISO date input.
- Select seconds or milliseconds when converting an epoch value.
- Convert and copy the UTC, local and Unix time formats.
What is a Unix timestamp?
A Unix timestamp counts elapsed time from 1970-01-01 00:00:00 UTC. Traditional epoch values use seconds, while JavaScript and many APIs use milliseconds. For example, 1700000000 seconds and 1700000000000 milliseconds identify the same instant. The number represents UTC time; a local timezone is only applied when that instant is displayed as a calendar date.
Are Unix timestamps seconds or milliseconds?
Ten-digit values commonly represent seconds and thirteen-digit values commonly represent milliseconds, but digit length is only a clue and becomes ambiguous for older or far-future dates. Choose the unit required by the source system instead of relying on automatic detection. JavaScript Date.now() returns milliseconds, while many Unix commands and database fields use whole seconds.
How do you convert ISO 8601 to epoch time?
Choose ISO date to Unix timestamp and enter a date containing either Z for UTC or a numeric offset such as +01:00. The converter resolves that exact instant and returns both seconds and milliseconds since the Unix epoch. Requiring an explicit timezone prevents a server date and a browser-local date from silently producing different epoch values.